What insect caused leaves to curl downward along the edges in cotton?

Aphids are known for causing leaves to curl downward along the edges in cotton plants. These small, soft-bodied insects feed on the phloem sap of plants, which can lead to various symptoms, including leaf curling. The curling occurs as a reaction to the stress induced by the aphids feeding on the plant sap, as the plant's physiological responses to the feeding may cause the leaves to deform.

In contrast, while other insects like army worms and budworms can cause significant damage to cotton crops, their feeding patterns typically lead to different types of symptoms, such as holes in leaves or defoliation rather than curling. Plant bugs also affect cotton but usually cause stippling or discoloration rather than the characteristic curling caused by aphids. This specific response of leaves curling downwards is a key indicator of aphid infestation, making it crucial for pest management in cotton production.